"Going wrong" indeed: Rendell's latest variation on a favorite theme--psychotically obsessive love--is surprisingly one-dimensional and padded out, without the sharp twists or convincing peril of her best (or even second-best) work. Rich, handsome, amoral, slum-bred Guy Curran, almost 30, is still utterly obsessed with childhood-sweetheart Leonora--even though they haven't been lovers for over ten years, even though she's an intellectual liberal who despises his gangsterish London life-style (and the drag-dealing in his past). True, for years Leonora has agreed to have Saturday lunches with Guy, and to take his daily phone calls. But now, to Guy's horror, Leonora announces her plans to marry a brainy, grabby fellow named William--and move to Manchester! So wild-and-crazy Guy, convinced that Someone has turned Leonora against him, determines to have that Someone killed--though Guy isn't quite sure whether the evil Someone is Leonora's snobbish mother. . .or her upstart brother. . .or her homely roommate. . .or. . .? Unfortunately, Guy's obsession--and the novel's only viewpoint--is never even close to believable. His unpleasant company, then, soon becomes tedious rather than frightening or fascinating. His repetitious fantasies and tirades suggest a short story artificially inflated to novel length (as does the book's limply ironic fade-out). And this is ultimately an obvious, monotonic psycho-suspense exercise--competently narrated (with occasionally intriguing details) but unworthy of the author of A Judgement in Stone, Make Death Love Me, and the Wexford detective series.